How do I access UCS by custom sub domain name of a domain I already own?

Also how do I add next cloud to its own subdomain? I am experienced in DNS, and reverse proxies, but not quite sure how to do this in UCS. Also how do I do it with cloudflares DNS? Last I am unable to access UCS by domain name. How is this done? For example I have created UCS to be under, but when I go to this address I can not access the server. I can only access the server by private IP. I am in a Virtual Machine using a bridged network.

I am also running a webserver on my second virtual box for my hosting platform. It is using OpenLiteSpeed right now. So How do I configure USC to use its internal webserver and Im sure I will have a port issue. How may I change which port the UCS server uses?

bump bump bump bump bump due to no response from the community.